New studies have found that using medical or recreational marijuana to treat symptoms of mental health conditions does not work, according to the studies in the journal Lancet Psychiatry. The research, which included Jack Wilson, a postdoctoral research fellow at the University of Sydney’s Matilda Centre for Research in Mental Health and Substance Use, found no evidence that any form of cannabis was effective in treating anxiety, depression or post-traumatic stress disorder. The study also found that marijuana did not improve other mental health issues such as anorexia nervosa, bipolar disorder; obsessive-compulsive disorder, or schizophrenia. Despite these findings, almost every state in the US approves medical marijuana for mental health purposes.